(19)
(11) EP 0 561 596 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
31.08.1994 Bulletin 1994/35

(43) Date of publication A2:
22.09.1993 Bulletin 1993/38

(21) Application number: 93301954.9

(22) Date of filing: 15.03.1993
(51) International Patent Classification (IPC)5: C08J 5/18, C08L 67/02, H01B 3/42
(84) Designated Contracting States:
DE FR GB

(30) Priority: 19.03.1992 JP 63444/92
19.03.1992 JP 63445/92
27.03.1992 JP 71093/92

(71) Applicant: TEIJIN LIMITED
Osaka-shi Osaka 541 (JP)

(72) Inventors:
  • Hamano, Hisashi
    Sagamihara-shi, Kanagawa-ken (JP)
  • Hosoi, Masahiro
    Nerima-ku, Tokyo (JP)
  • Nishiyama, Masanori
    Sagamihara-shi, Kanagawa-ken (JP)
  • Saeki, Yasuhiro
    Sagamihara-shi, Kanagawa-ken (JP)

(74) Representative: Votier, Sidney David et al
CARPMAELS & RANSFORD 43, Bloomsbury Square
London WC1A 2RA
London WC1A 2RA (GB)


(56) References cited: : 
   
       


    (54) Oriented polyester film


    (57) An oriented polyester film (A) which comprises modified polyethylene-2,6-naphthalenedicarboxylate containing a 4,4'-diphenyldicarboxylic acid component and having a heat of crystallization of 16 to 25.5 Joule/g, and (B) which is biaxially oriented; and an oriented polyester film (A') which comprises modified polyethylene-2,6-naphthalenedicarboxylate containing of a glycol component derived from a compound represented by the following formula,


       wherein each of n and m is independently a positive number of 1 to 9 as an average, provided that m + n equals 2 to 9 as an average.
    and having a heat of crystallization of 6 to 20 Joule/g, and (B) which is biaxially oriented. These films are useful as a base film for a magnetic recording tape or as an electric insulation film.





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